We have continued our systematic placement of cDNAs on chromosomes and YAC clones, so far determining the chromosomal location of approximately 1,400 genes. We have developed a rapid ELISA approach for analysis of PCR products and have applied this technology, along with robotic support and novel analytical computer software, to allow rapid, high-throughput mapping of PCR products derived from the 3' untranslated regions of cDNAs. The ultimate goal is to place the vast number of expressed sequence tags (ESTs) on the map, making them instantly available as candidate genes in any region of the genome in which medical researchers have localized the locus for a disease.